Game Development Reference
In-Depth Information
How to do it...
We'll start by defining a
GatherResourceState
class. It extends the same
AIState
we defined in the
Decision making - Finite State Machine
recipe. This will be implemen-
ted by performing the following steps:
1. First of all it needs access to the AIControl called
aiControl
.
2. It needs two additional fields, a
Spatial
defining something to pick up called
resource
, and an integer called
amountCarried
.
3. In
controlUpdate
method, we define two branches. The first is for if the unit
isn't carrying anything,
amountCarried == 0
. In this case, the unit should
move towards
resource
. Once it gets close enough, it should pick up some, and
amountCarried
should be increased, as shown in the following code:
Vector3f direction =
resource.getWorldTranslation().subtract(this.spatial.getWorldTranslation());
if(direction.length() > 1f){
direction.normalizeLocal();
aiControl.move(direction, true);
} else {
amountCarried = 10;
}
4. In the other case,
amountCarried
is more than
0
. Now, the unit should move
towards the HQ instead. Once it's close enough,
finishTask()
is called.
5. The
finishTask
method calls the AI Manager via
aiControl
to increase the
resource amount that the state handles with the supplied amount as follows:
aiControl.getAiManager().onFinishTask(this.getClass(),
amountCarried);
amountCarried = 0;
6. Finally, we create two new classes that extend this class, namely
Gather-
FoodState
and
GatherWoodState
.
With the new state handled, we can focus on the
AIControl
class. It will follow the pat-
tern established elsewhere in the chapter, but it needs some new functionality. This will be
implemented by performing the following three steps:
